Systems and methods for power generation utilizing combustion of fossil fuel(s) with carbon dioxide as a working fluid are described in U.S. Pat. No. 8,596,075, which is incorporated by reference in its entirety herein. Such systems and methods utilize substantially pure oxygen for the combustion of the fossil fuel at high pressures (e.g., approximately 200 bar to 500 bar) and high temperatures. In some examples, the fossil fuel may be natural gas (i.e., hydrocarbon gas mixture consisting primarily of methane), and/or a fossil fuel derived from the partial oxidation of coal, biomass and/or residual petroleum refining products such as, for example, heavy residual oil fractions or petroleum coke. Regardless of the fossil fuel, highly pressurized gaseous oxygen is required in large quantities. Such systems and methods have been shown to provide increased efficiency through addition of heat to the power generator that is not recuperated from the combustion product stream. In one aspect, the added heat may be derived from adiabatic heat produced by compressors that increase the pressure of an inlet air stream in a cryogenic oxygen production process and/or from carbon dioxide recycling compressors.
Atmospheric air is recognized to comprise a number of different gaseous components, primarily nitrogen and oxygen, but also minor amounts of other materials, such as noble gases (predominantly argon), methane, water vapor, and carbon dioxide. One or more of the components of atmospheric air can be separated and provided in a purified form with an air separation method and system (i.e., an “air separation unit,” “air separation plant,” or “ASU”). There are various known technologies that are used for the air separation process, such as cryogenic distillation (e.g., a cryogenic air separation cycle), membrane separation, pressure swing adsorption (PSA), and vacuum pressure swing adsorption (VPSA) and separation of oxygen from air in a high temperature oxygen ion transport ceramic mixed oxide membrane system. Of the various available methods, cryogenic distillation is particularly advantageous for separating air into its constituent parts at high purity and high pressure.
A pumped liquid oxygen cycle is one exemplary cryogenic air separation cycle utilized for producing high pressure oxygen. For example, a pumped liquid oxygen cycle utilized for a cryogenic air separation cycle may include a liquid oxygen pump configured to deliver high pressure liquid oxygen through a heat exchanger so as to heat the high pressure liquid oxygen to ambient temperatures by cooling and/or condensing a complementary stream of high pressure air or nitrogen.
Although large scale oxygen production for industrial processes has been practiced for over 100 years, the highest oxygen pressures used up to now have only approached approximately 100 bar. Oxygen has been produced for high pressure gas cylinders at pressures of over 300 bar, but this production process for generally low flow rates utilizes small reciprocating pumps pumping liquid oxygen and then subsequently heating the liquid oxygen to ambient temperatures indirectly with an indirectly heated heat exchanger, for example using heat supplied externally from ambient air or hot water. Accordingly, there remains a need in the art for further systems and methods for production of high pressure oxygen, such as suitable for use as an oxidant in a power production system and method.